146 THE RISE AND PROGRESS OF PHOTOGRAPHY. 
I propose dividing my ede ae two parts—firstly, the history 
and progress of pesca ell ; secondly, its practice and applica- 
tions. In tracing to its abstract rr history of any great sangre! 
which has not been su a or fortuitous, but whic s bee 
gained by deep study and oft repeated. gee we find two prominent 
things, the idea that caused the wish, and the means for t 
perception of the fulfilment of that vik 
The one is the essence and the other the substance, and they 
‘are as important to each other as soul to body. These are repre- 
sented by certain substances which have from time to time been 
noticed to darken under the sdiiaede | of white light, — the 
will 
now see how photography came into existence and to en we 
are indebted for our knowledge in its present advanced state. 
- Assertions have from time to time appeared in print crediting 
both the Chinese and Japanese with having possessed the 
uncertain theories sok he a aut hie hicndeed ears. e 
alchemists certainly knew of the existence of chloride of silver, as 
verified Py Fabricius about the ve et in ee work “ De rebus 
metallicu Again we find it in a very singular work by 
Tepinigns de la Roche, entitled y Giphantie 4 Babylone,” who 
supposed himself transferred to the palace of the genii of the 
element, the chief of whom thus addrepeed him 
faithfully. 
after you h re precious, trut 
The spirit then 
